learn / Stay in Sync: The Circadian Rhythm

Our bodies are constantly switched on. With a never-ending to-do list, from hormone production to digestion, muscle repair to toxin removal, it relies on an internal clock called the Circadian rhythm to get it all done. This clock organises the timings of certain tasks to optimise our biological functions.

Though largely regulated by light and food, we can actively work to keep it in check and stay in great health, as being out of sync with this clock puts us at a higher risk of developing disease (something worth remembering next time you reach for a late-night snack or snooze your alarm…). The good news is it is easy to stay in time.

Eat all your meals within 12 hours.

Eating around the clock is associated with a variety of disadvantages, not least a higher body weight and difficulty sleeping. Eating before bed stimulates the digestive system, contradicting the hormone melatonin that is telling it to wind down for the day. The result is an overload of food in a system that is not expecting it. Experts recommend at least 3 hours between your last meal and your head hitting the pillow to facilitate digestion and avoid restlessness. Furthermore, people that eat all their meals within a period of 8-12 hours experience a deeper sleep, on top of drifting off quicker.

Keep light levels low at night-time…

Staying under blue light for just one hour in the evenings can completely reset your Circadian clock, making your body think it is morning. Don’t worry – we do not expect you to sit in darkness once the sun goes down. Opting for table lamps instead of overhead lighting can considerably reduce exposure to blue light. It may also be worth investing in dimmer switches to minimise lighting levels, as well as making sure that your device’s Night Shift mode is switched on, as this will adjust the blue light emitted from the screen. This is particularly important for adolescents and younger adults, as their Circadian rhythms operate slightly later into the evening, with melatonin release occurring as late as 11pm.

Go outside in the daytime.

The modern lifestyle does not always cooperate with our Circadian clocks. We spend so much time indoors that we rarely receive the light we need to tell our bodies that it is daytime (and then we stay up later, turning on all the blue lights as we go). This delays melatonin production, leaving us wide awake at bedtime. The solution is simple: go outside and make the most of the daylight hours. Though there is little difference in performance, exercising outside in the mornings is a great way to regulate your Circadian rhythm and boost your mood for the whole day. On the other hand, exercising too late at night will bring your cortisol levels up to those of the morning and disrupt your sleep.

Get into a routine so that your activities (sleep, food and exercise) do not differ day to day by +/- 2 hours.

Having a lie-in every weekend, as indulgent as it may seem, is only going to jeopardise your weekday routine. Everybody knows how exhausting it is to cross time zones, so imagine doing it every weekend. The simple act of staying up late and waking up late on the weekend mimics the symptoms of jetlag, resulting in an exhausting Monday morning. In fact, experts estimate that it takes one whole day per time zone crossed to adjust. In other words, sleeping in until 10am when you normally get up for work at 7am will have the same effect on your body as travelling from New York to Los Angeles… and take 3 days to recover from. A great way to clear any sleep debt that may be lingering after a late night is a mid-afternoon nap. Not only will you feel better rested, but also you are more likely to retain information learned that day.

An out-of-sync Circadian rhythm can result in a number of ailments, and yet, we hardly look at our sleeping habits as the underlying cause. Low moods, struggling to maintain a healthy weight and a weakened immune system are all symptomatic of a chronic lack of good quality sleep. With this in mind, trying just one or two of these tips might alleviate problems in other areas of your life, as well as protecting the necessary functions of a healthy body.